Liquid flow regulating system



May 27, 1952 u. J. RUTGERS LIQUID FLOW REGULATING SYSTEM Filed Dec. 12, 1949 INVENTOR" Flak/z Jazz Eager;

Patented May 27, 1952 LIQUID FLOW REGULATING SYSTEM Ulrich Jan Rutgers, Arnhem, Netherlands, as-

signor to American Enka Corporation, Enka, N. 0., a corporation of Delaware Application December 12, 1949, Serial No. 132,437 In the Netherlands January 4, 1949 2 Claims.

The present invention relates to a system for the continuous and uniform supply of a low viscosity liquid to a spinning solution by means of a pipe system, and more particularly the invention relates to a device for minimizing the pressure differential in and around the metering pump in the main supply line.

In the manufacture of synthetic threads, filaments, and the like, it is often desirable to add certain substances to the spinning solution in order to modify or improve the characteristics of the products formed therefrom. These substances are added in the form of emulsions or dispersions such as those formed from a suspension of pigments, dyes, carbon black, oils, etc., and the emulsion of suspension thereof is preferably added to the spinning solution during the period that the spinning solution is being pumped to the spinning machine for the purpose of extruding the same into filamentary products,

The supply of the liquid emulsion or dispersion to the spinning solution is effected normally by means of metering pumps, the most suitable being positive displacement pumps of the gearwheel type. These pumps are well adapted for supplying highly viscous liquids, but in the case of supplying W viscosity liquids as those contemplated by the present invention, difficulties arise due to the fact that the liquids are supplied under a relatively high pressure, which pressure is irregular as a result of a combination of several factors inherent in the various processes and notably in the viscose process. These pressure variations are reflected in the supply lines creating a pressure differential before and after the meterin pump, which results in an irregular supply of the liquids to the spinning solution.

Since small variations in the quantity of liquid added to the spinning solution exert a marked effect on the properties of the resulting products such as uneven dyeing and delustering, it is apparent that the liquids should be added to the spinning solution at a constant and uniform rate.

It is therefore an object of the present invention to provide a system in which low viscosity liquids are supplied under pressure to a spinning solution in a constant and predetermined quantity.

It is a further object of the invention to minimize the pressure differential before and after the metering pump used to pump a low viscosity liquid to a spinning solution.

It is also contemplated to provide a novel pressure regulating device in a branch pipe line that regulates the flow of liquid therethrough as a result of changes in pressure in the main supply line of the liquid being supplied to the spinning solution.

Another object of this invention is to conform the pressure before the metering pump to the pressure after the metering pump by utilizing, in a branch pipe line before the metering pump, an elastic coupling that varies the rate of flow of liquid through the branch line in accordance with pressure variations in the main supply line.

Other objects and advantages of this invention will be apparent upon consideration of the following detailed description, when considered in conjunction with the accompanying drawing, wherein the single figure represents a schematic flow diagram illustrated in partial section to show the structure and operation of the liquid pressure regulating device.

Referring to the drawing, the numeral l0 indicates the spinnin solution line for conducting the spinning solution to the spinning machine proper. Stock tank H contains a low viscosity liquid emulsion or dispersion l2 to be ultimately supplied under pressure to the spinning solution line H! by Way of a pipe system indicated generally at I 3.

The liquid I2 is drawn through pipe [4 and three-way valve l5 by means of auxiliary gear pump 16 and metering gear pump l'l. Valve 15 connects pipe [4 to main pipe line l8 during normal operation when the liquid is being supplied to the spinning solution in spinning solution line It.

Metering pump I1 is regulated to pump a predetermined quantity of liquid through the main pipe lines 19 and 20 to the spinning solution line It. Auxiliary gear pump I6 is driven at a considerably higher speed than metering pump ll so that the output of pump [6 is considerably greater, even as much as ten times as large as the output of pump Ii. Accordngly, most of the liquid pumped through main pipe line 2| is bypassed through branch pipe line 22, with the small residual portion going through metering pump H. The by-passed portion of liquid flows from branch pipe line 22 through a pressure regulating device generally indicated at 23 and back into main pipe line l8 before auxiliary pump is via branch pipe line 24.

The pressure regulating device consists of an elastic coupling 25 such as a rubber tube that connects branch pipe lines 22 and 24. This elastic coupling is surrounded by an air-tight shell 26 having a liquid inlet 21 and a liquid outlet 28 for accommodating the passage of liquid from the main pipe line I 9 to the main pipe line 20.

It is apparent from the foregoing flow diagram that as the back pressure builds up or fluctuates in the spinning solution line H] carrying the spinhing solution, such pressure changes will be reflected back through main pipe line 20, pressure chamber 29 in the pressure regulating device 23 and main pipe line I9. This pressure will therefore increase or change after metering pump l1. When this pressure changes, for example, in-

creases, the increase will be transmitted to pressure chamber 29 and close or tend to close the elastic coupling 25, which in turn will retard the passage of liquid through the coupling, thereby increasing the pressure in branch .pipe line 22, which will in turn, increase the pressure in main pipe line 2| and thereby conform the pressure before the metering pump H to the pressure thereafter. Conversely, as the pressure decreases in pipe lines 20 and I9, the decrease .will allow the coupling 25 to resume its normalposition 2&- celerating the passage of liquid therethrough, which will in turn lower the pressure in branch pipe line 22 and main pipe line 2i. In this way the pressure differential before and after metering pump 17 is min mized, and in practice, .has been found to be reduced under 0.2 atmosphere when a very flexible rubber tube is usedas the couplin in the pressure chamber. It is desirable that the tube be extremely elastic so as to respond to pressure changes immediately and close when the pressure increases after the metering pump and in the pressure chamber. This will maintain the pressure the same inand around the metering pump even though the difiereneein pressure in branch pipe lines 22 and 24- may be as much as 4 atmospheres. Thepressure before and after the metering pump H is indicated on pressure gauges 39 and 3!, respectively.

During normal operation, the three-way valve 15 connects pipe I l to main pipe line i8 so that liquid is being supplied to the spinning solution. However, the valve l5 can also be used to permit the measurement of the time required for a predetermined quantity of liquid to be exhausted from measuring vessels 3.? and 33. This can be accomplished by rotating the valve 180 from the position shown in the figure, whereby the measuring vessels 32 and 33 are connected to main pipe line [-8, but the supply from the tank H is cut off. In the position shown in the figure, the supply from tank I! is connected to main pipe line [8, while at the same time the supply is connected to the measuring vessels 32 and 33 for filling the same during normal operation.

In'order to prevent seepage into main pipe line 20 as a result of back pressure on the spinning solution, a non-return valve 3% is provided at the junction of main pipe line .213 with the'spinning solution line L9 i 4 What lsclaimed is: 1. 'Alsystem' for constantly supplying a predetermined quantity of low viscosity liquid to a spinning solution which comprises a main pipe line forsupplyingthe liquid to the spinning solution, a metering pump in the main line for controlling the quantity of liquid supplied, a branch line connected to the main line before the metering pump, an auxiliary pump in the main line upstream .of the branch line constructed and arranged to operate at a higher capacity than the metering pump whereby excess liquid is by-passed to the branch line before the metering pump, means, responsive to pressure changes in the main line .downstreamof the metering pump, to regulate the .flow of liquid in the branch line whereby the pressure before the metering pump conforms 'to' the pressure after the metering pump.

2. A system for constantly supplying a predetermined quantity of low viscosity liquid to a. spinning solution .Which comprises a main pipe line for supplying the liquid to the spinnin solution, a metering .pump in the main line for controllingtheqnantity of liquid supplied, a branch line connectedtothe main line before the metering pump, an auxiliary pump in the main line upstream of the branch line constructed and ar ranged .to operate at a higher capacity than the metering pump whereby excess liquid is by-passed to' the branch line before the metering pump, an elastic coupling in the branch line and a pressure chamber surroundin the said coupling and connected to the main line whereby pressure fluctuations in the main line after the metering pump will regulate the flow of liquid in the branch line and thereby conform the pressure before the metering pump to the pressure after the metering pump.

ULRICH JAN RUTGERS.

Name Date Callan July 9, 1318 Number 

